I'm getting back into Ars Magica after a decade or so, just picked up 5th edition. I realize that these may be old, frequently asked, questions.
When exactly does a Year/Moon/Day end? A long time ago I invented a ReVi spell that worked like Watching Ward, not ritual, with duration Sun. The idea being that it would expire when the Parma Magica did, and at sunset while a wizard was recasting the Parma the attack spell would take effect and catch 'em with their magic resistance down. I don't have a problem with the Parma having some "overlap" by design, or even spells overlapping by a Diameter (at sunset, one spell starts when the sun hits the horizon, the other ends when it goes entirely below) but I was wondering if there was a standard answer to this. Likewise with Aegis of the Hearth. Do all the magi in the castle get up an hour-ish before sunrise so casting finishes in the diameter of sunrise? Are they lazy?
Speaking of Parma: Almost the only difference in phrasing between "Wind of Mundane Silence" and "Unravelling the Fabric of (Form)" is that the Wind can blow down Parma and Unravelling, presumably, cannot. Would it be possible to create "Unravelling the Fabric of Parma Magica"? Is this the sort of thing that makes House Bonisagus suppress a discovery? One can make a case that this spell cannot be developed; Flambeau himself spent years trying to develop a way to break the Parma Magica and could not (according to Societes.) Are there standard opinions on this?
Some context: Imagine I were to turn rock into dust with Perdo Terram and thus silently dig a cave deep under a covenant. When it gets too large, I hold up the ceiling with CrTe ritual pillars, duration Year, cast after the winter solstice, and continue digging. On the next winter solstice, as Aegis of the Hearth is being recast, the pillars expire and the cave collapses; the covenant falls into a giant sinkhole and the enemy magus is nowhere within a hundred miles at the time. Assuming the residents did everything right, is the Aegis up?
"Year" lasts four seasons each marked by its respective solstice/equinox. Thus for example, if I cast an Aegis of the Hearth today, the spell would persist until the Winter Solstice (December 21), but were I to wait and cast it this Thursday, it would last until the Vernal Equinox (March 20) of next year instead!
Similarly, "Day" ends at dawn or dusk (whichever is nearer), "Moon" lasts long enough for both a Full and New moon to occur.
The short answer is that, while invented by Bonisagus and (theoretically) only known to Hermetic Magi, Parma Magica does not constitute hermetic magic for the purposes of dispelling. Parma can be dispelled, however. One chapter "Hermetic Projects" features the concept quite prominently. Of course, you still have to penetrate with the effect first...
I'm not sure I understand the question completely, but as I see it the covenant's Aegis wouldn't confer any protection against the attack you described anyway.... I believe the matter may have come up in HoH: TL, but I'll have to plead Serf's Parma for now...
-That being said a watching ward like spell would have problems. IMHO is that the hung spell is cast on the "target" then the effect is immediately suppressed. So the spell would have to overcome the "target's" MR when cast not the MR when it goes off. Not that there aren't a dozen ways to get around (or exploit) this.
-As far as how diligent Magi are about recasting Parma. That should entirely vary by saga and character. Though IMO most magi would be in the habit of waking up and recasting their parma at dawn. Less out of paranoid self protection and more out of habit. Meaning unless they have some sort of character trait or condition it would be unreasonable for another Magus or the SG to assume that they would be unprotected for more then a few minutes.
-Yeah ditto to what Gremlin said.
-Casting a big Ritual like Aegis can't be timed out to the exact moment your previous spell expires in my opinion. I would imagine everyone would actually be out walking the perimeter of the covenant when it collapses. So I'm sure the ritual would not be finished.
I could have sworn that was reasonably well-defined in the core book?
Parma Magica appearantly is a well-known Hermetic effect that does not fall under any of the Arts. Dispelling it is explored in Projects (as mentioned above) and touched upon slightly in Magi of Hermes (Cultellus, p. 31). Please note that such an effect has to penetrate said Parma Magica.
The Aegis would have probably affected you digging and creation of pillars (NB: Remember that D: Year is always a ritual and so requires Vis!).
I think you're trying to ask in a T: Boundary spell fails if the defined boundary fails? I'm not sure, but I don't think so - that's really a feature of D: Ring/T: Circle.
As far as Parma, I will check "Hermetic Projects"- I wasn't aware there was such a book.
#3 (and, thus, #1) obviously needs clarification.
Tactically, collapsing a covenant is very likely to leave survivors. They're magic, they fly and suchlike. If you want to swoop in and massacre the survivors, the question of exactly when the various events happen matters.
Event A: Aegis of the Hearth ends at sunrise on the Winter solstice.
Event B: New Aegis of the Hearth starts about at sunrise on the Winter solstice.
Event C: Magically created pillars fail and covenant starts falling into the sinkhole, at sunrise on the Winter solstice. Enemy magi start shooting survivors with Pila of Fire and throwing big rocks and whatever else appeals to their sense of theater.
Sunrise takes a Diameter for the sun to go from "all the way down" to "all the way up". There are 2 minutes, something like 20 rounds, of ambiguity here. If the home team has really good timing, so that the Aegis spellcasting completes within the two minutes that the sun is partly obscured by the horizon, do A and C happen before B? If the Aegis (or Parma) is specifically designed to last through the process of sunrise, to avoid sunset sucker punches, does C happen before A?
I ) I am assuming that the cave, which is far below the ground and not connected to the Covenant grounds in any way, is not covered by the Boundary of the spell, but I'm very willing to hear counterarguments. Does the Aegis go all the way up to the lunar sphere and down to Hell? Seems like it's gotta stop SOMEWHERE that is obviously not "of" the covenant, even if the exact boundary is not obvious.
II ) I agree, it requires vis to cast the spells that keep the cave from collapsing. If you're planning on massacring a bunch of magi and you don't plan on investing SOME vis, you aren't really trying.
Yup. If as by tradition it was cast on the solstice the year previously.
Maybe. A powerful Aegis is an hours long ritual that traditionally involves the whole covenant not just the wizards casting it. Timing it out so the ritual ends within moments of last years aegis expiring is a tricky and possibly expensive undertaking. Finish five minutes early and you have to cast the next aegis 3 months sooner on the autumn equinox.
Sure I suppose. If you assume that the Magi are finishing casting the Aegis or even mostly done they will be on outer boundary of their covenant. So they are unlikely to be seriously affected by the cave in. Their Parmas will be down, but so will the attackers so both parties will probably pause to raise them. This makes it pretty close to a fair fight.
Timing a group activity with that kind of accuracy would be a challenge of leadership skills and logistics even today. People in 1220 AD would have an entirely different concept of what "on time" means. Mechanical clocks are just being invented, they aren't very accurate and won't even have minute hands for several more centuries. Even the hourglass has only been around a short time.
Personally I don't think most covenants try to hard to time it exactly. They probably just try to get it cast as soon as they can on the day of the solstice. I would talk to your SG and troupe and try to figure out what you all expect the standard practice to be for covenants.
Is it below there cellars, how far? Is it below the bottom of their well? If so these caves would be filled with water without further magic. I would imagine an Aegis extends at least this far if not farther. It's fair to say it that from bottom to top it's at least as tall as a standard Boundary is wide. Depending on the geology a cave dug that deep might not cause an instant collapse.
Yes but that's a lot of vis.
One other point the pillar spells, and therefore most all your excavation, would have to be cast over a three month period starting exactly a year before your planned attack.